冷缝存在条件下混凝土力学性能试验研究  

Experimental study on mechanical properties of concrete with cold joints

作　　者：覃源[1] 梁达 王玉龙 柴军瑞[1] 周恒 QIN Yuan;LIANG Da;WANG Yulong;CHAI Junrui;ZHOU Heng(School of Water Conservancy and Hydropower,Xi′an University of Technology,Xi′an,Shaanxi 710048,China;Power China Northwest Engineering Corporation Limited,Xi′an,Shaanxi 710065,China)

机构地区：[1]西安理工大学水利水电学院,陕西西安710048 [2]中国电建集团西北勘察设计研究院有限公司,陕西西安710065

出　　处：《排灌机械工程学报》2023年第7期677-681,688,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51679197);中国博士后科学基金资助项目(2014M562524XB)。

摘　　要：存在于混凝土中的冷缝,直接影响混凝土结构的整体性能.通过对不同龄期间隔的冷缝,及不同弹性模量混凝土叠合形成的带冷缝的混凝土进行抗压和劈拉试验,研究其力学性能的变化规律.试验结果表明:带冷缝混凝土试件整体抗压强度及冷缝黏结面黏结强度均随龄期增长逐渐减弱,新混凝土强度提升,可有效提高带冷缝混凝土的抗压强度,而对黏结面强度提升较为有限;通过计算岩石脆性特征系数发现,新混凝土强度提升可有效提高新旧混凝土抗变形能力;并建立了冷缝黏结面强度计算公式,可以较好地预测冷缝黏结面的黏结强度.当龄期间隔7~14 d,新、旧混凝土弹性模量之比为1.10时力学性能较好,龄期间隔超过28 d时,新、旧混凝土弹性模量之比应小于1.10.Cold joints in concrete directly affect the overall performance of concrete structures.Compressive tests and splitting tensile tests were conducted on the concrete with cold joints formed by the cold joints at different ages and the concrete with cold joints formed by the superimposed concrete with different elastic modulus,the variation law of its mechanical properties was studied.The results show that the overall compressive strength of concrete specimens with cold joints and the bonding strength of the cold joints bonding surface are gradually decrease with the growth of age.The strength of new concrete is increased,which can effectively improve the compressive strength of concrete with cold joints.However,the improvement of the bonding surface strength is relatively limited.By calculating the rock brittleness characteristic coefficient,it is found that the strength improvement of new concrete can effectively improve the deformation resistance of old and new concrete.A formula for calculating the strength of cold joint bonding surface is established,which can predict the bonding strength of cold joint bonding surface well.When the age interval is about 7 to 14 days,and when the ratio of elastic modulus of new and old concrete is 1.10,the mechanical properties are better.When the age interval is more than 28 days,the ratio of elastic modulus of new and old concrete should not be more than 1.10.

关 键 词：冷缝 龄期间隔 黏结强度 弹性模量比 破坏形态 

分 类 号：S277.9[农业科学—农业水土工程]